R975 Radials

[David Dunlop]

Interesting alternate thread on the proper operation of these engines in the Sherman Tank and Sexton got me wondering when production of the Sherman with these engines actually stopped.

There seems to be at least three different types of power plants used in various Shermans. One reads of the massive supply of these tanks leading up to D-Day and of how crews from knocked out Shermans could get another vehicle out of reserve stock so quickly and be back in action. It sounds so easy on paper, but what if you have been operating a tank for months with something other than a radial engine and the next tank you receive is radial equipped? Your learning curve for safe operation of the radial is going to be very short. Makes me wonder to what extent engine failures from inexperience took Shermans out of action.

David

[maple_leaf_eh]

I would expect someone realized this too, and tried to keep like types in the same supply stream.

Off the top of my head, the story of engine choices was more about large scale supply mathematics effecting outcomes and not just about convenience. When airplane manufacturers changed from radial to inline, that capacity had to be applied somewhere. Knowing that the M3 and M4 hulls were designed for tall engines, adapting engines to bodies vs redesigning the hulls would have been easier. Who in their right mind would willingly inflict the Chrysler multibank when radials or V-blocks were available?

[rob love]

Originally Posted by maple_leaf_eh

Who in their right mind would willingly inflict the Chrysler multibank when radials or V-blocks were available?

Who in their right mind would willingly inflict a petrol engine of any type in a tank when the Detroit diesel was available. They should have been converting the radial factories into 6-71 factories.

Something about intense heat, gasoline, and high explosives while being shot at makes me prefer the diesel.

[motto]

The Sherman with the Chrysler Multi Bank (M4A4?) actually had a hull modification as it was some inches longer in the engine compartment to fit it in. Many thousands of tanks were produced with that power plant so it must have been viable or there was a gap to be filled that couldn't be filled in a more expedient manner.
I have no idea how they performed in comparison to other engines and would be curious to know.

David

[tankbarrell]

Originally Posted by motto

I have no idea how they performed in in comparison to other engines and would be curious to know.

David

Very well. Mine has just finished filming with four others, an M4A1, an early M4A2, a late M4A2 and an M4 late with a modern Mercedes diesel.

[Keith Webb]

Are there any of those Chryslers still running?

Here we had the triple sidevalve V8 Cadillac engine, called I think the Perrier Cadillac.

[tankbarrell]

Yes, my M4A4 has its original engine. As far as I know there are four multibanks running worldwide.

[Keith Webb]

Do you have some video of it? Be interesting to hear what it sounds like.

[tankbarrell]

Keith, not my video but my tank! Sound is not brilliant but it gives a taste.
http://www.youtube.com/watch?v=RYxKhEIHUCU

[Keith Webb]

Thanks for sharing that, what a ride!

[Lynn Eades]

Adrian, How are they synchronized? by the ignition, I would presume, but do tell please.

[motto]

Adrian forgot to mention that he did a total rebuild of the engine in his tank Keith. Quite a task by anyones reckoning.

David

[tankbarrell]

Originally Posted by Lynn Eades

Adrian, How are they synchronized? by the ignition, I would presume, but do tell please.

Lynn,

the engines are permanently geared together so no need to synchronize in the same way as the twin Detroits for example. Obviously it is possible to have the ignition timing beyond ideal for where the engine is running but that is not hard to set correctly.

[Roger Lucy]

Originally Posted by David Dunlop

There seems to be at least three different types of power plants used in various Shermans. One reads of the massive supply of these tanks leading up to D-Day and of how crews from knocked out Shermans could get another vehicle out of reserve stock so quickly and be back in action. It sounds so easy on paper, but what if you have been operating a tank for months with something other than a radial engine and the next tank you receive is radial equipped? Your learning curve for safe operation of the radial is going to be very short. Makes me wonder to what extent engine failures from inexperience took Shermans out of action. David

Actually there were 5 types of engines used with the M4 Sherman: the Continental R975, GM 6046 Diesel; the Ford GAA V8 , the Chrysler A57 multibank and the Caterpillar D200A diesel. Diesel engined tanks were in relatively short supply, because the US Navy had first call on diesel engine production.

The way Shermans were allocated tended to avoid problems of units coping with different engine types. So diesel-engined Sherman IIIs (M4A2) generally went to the USSR. which preferred diesels, the Americans kept the Ford V8s Sherman IVs (M4A3) for themselves, the UK largely standardised on radial engined Sherman Is and IIs (M4 and M4A2) passed its Sherman Vs with multibank engines (M4A4) to Canada. The Chrysler engine was not the Canadian Army Overseas preferred choice as it was complex to service but it did deliver more power and torque than the Continental R975 on the Ram, Grizzly and Sexton. The R975 C-4 was certainly used down to July 1945 when the last Sextons were delivered.

As an aside the Germans are often criticised for their lack of standardisation of their armour, but when it came to engines, their principle battle-tanks and their assault-gun Jagdpanzer variants, essentially used only two engine types: the Maybach HL120 TRM on the Pz.III and Pz.IV and the Maybach HL230 on the Tiger and Panther. In addition to the Sherman's array of engines the British also had the Nuffield Liberty engine on their Crusader and Centaur tanks and the Meteor on the Cromwell and Comet.

[tankbarrell]

That's not really true. The British Army had nearly all of the M4A4 production and nearly as many M4A2. The radial tanks were the least preferred of the lot. Whilst many M4A2 and M4A4 were used by all the Commonwealth Armies, they were still the most common types in British formations.

[Perry Kitson]

To answer David's question, the last radial engine Sherman was a M4A1(76)W that was accepted for service July, 1945. I believe a Baldwin production vehicle, that just happens to reside north of Detroit in a private collectors hands.
Canada used M4A2's and A4's. An interesting note on the A2's is that the "Holly Roller" of the First Hussars here in London, and "Bomb" of the Sherbrookes had sequential CT numbers, both now monuments.
The A2 engine was by far the best performer off road, with a combined torque rating of almost 1800 ft/lbs. The biggest reason for the US not using the A2 Shermans (other than those used by the Marines) was their distaste for supplying two fuel types. The US preferred the Ford GAA as a first choice, the R975 radial (in the M4/M4A1) as the second.

Perry

[Harry Moon]

Originally Posted by rob love

Who in their right mind would willingly inflict a petrol engine of any type in a tank when the Detroit diesel was available. They should have been converting the radial factories into 6-71 factories.

Something about intense heat, gasoline, and high explosives while being shot at makes me prefer the diesel.

Logistics! Gas lots and lots of Gas via pipeline right to the front. Check out operation Pluto...